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rcu: Add support for debug_objects debugging for kfree_rcu()

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This commit applies RCU's debug_objects debugging to the new batched
kfree_rcu() implementations.  The object is queued at the kfree_rcu()
call and dequeued during reclaim.

Tested that enabling CONFIG_DEBUG_OBJECTS_RCU_HEAD successfully detects
double kfree_rcu() calls.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ paulmck: Fix IRQ per kbuild test robot <lkp@intel.com> feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Joel Fernandes (Google) 2019-09-22 13:03:17 -07:00 committed by Paul E. McKenney
parent 0392bebebf
commit e99637becb
1 changed files with 8 additions and 0 deletions
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8
kernel/rcu/tree.c
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@ -2749,6 +2749,7 @@ static void kfree_rcu_work(struct work_struct *work)
for (; head; head = next) {
next = head->next;
// Potentially optimize with kfree_bulk in future.
debug_rcu_head_unqueue(head);
__rcu_reclaim(rcu_state.name, head);
cond_resched_tasks_rcu_qs();
}
@ -2855,6 +2856,12 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
spin_lock(&krcp->lock);
// Queue the object but don't yet schedule the batch.
if (debug_rcu_head_queue(head)) {
// Probable double kfree_rcu(), just leak.
WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
__func__, head);
goto unlock_return;
}
head->func = func;
head->next = krcp->head;
krcp->head = head;
@ -2866,6 +2873,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
}
unlock_return:
if (krcp->initialized)
spin_unlock(&krcp->lock);
local_irq_restore(flags);